The synaptotagmin C2B domain calcium-binding loops modulate the rate of fusion pore expansion.

ABSTRACT: In chromaffin cells, the kinetics of fusion pore expansion vary depending on which synaptotagmin isoform (Syt-1 or Syt-7) drives release. Our recent studies have shown that fusion pores of granules harboring Syt-1 expand more rapidly than those harboring Syt-7. Here we sought to define the structural specificity of synaptotagmin action at the fusion pore by manipulating the Ca²⁺-binding C2B module. We generated a chimeric Syt-1 in which its C2B Ca²⁺-binding loops had been exchanged for those of Syt-7. Fusion pores of granules harboring a Syt-1 C2B chimera with all three Ca²⁺-binding loops of Syt-7 (Syt-1:7C2B₁₂₃) exhibited slower rates of fusion pore expansion and neuropeptide cargo release relative to WT Syt-1. After fusion, this chimera also di

SUBMITTER: Bendahmane M 

PROVIDER: S-EPMC5905296 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature